The present invention relates generally to imaging systems, and more particularly to techniques for identifying images in a series that are particular interest for viewing, storing, processing, and so forth.
Many imaging systems are known and are presently in use that produce images viewable on a computer or similar viewing station. The images typically comprise a matrix of pixels arranged in rows and columns that can be controlled in gray level or color to provide a composite recognizable and useful image. In the medical diagnostic context, for example, image data may be generated by a range of imaging modalities, such as X-ray systems, MRI systems, CT systems, PET systems, and so forth. The resulting digital images can be stored, compressed, transmitted, and eventually reconstructed from the image data. Large numbers of images can be acquired at a single session or over multiple sessions. Selecting and viewing images of particular interest is a challenge, however, when large numbers of images in a series are available.
Again, in the medical diagnostics context, with the advent of multiple slice CT scanners, for example, a number of images are acquired in a single scan session. CT scanners commonly allow for acquisition of 8 and 16 slices through a subject of interest at once. While in the past particular imaging sessions or studies may have contained 1 to 200 images, many more such images can now be acquired. A viewer, such as a radiologist, would generally navigate through such images by visual inspection, using cine or stacked mode displays.
Continuing with the example of CT imaging, such techniques have been extended to provide cast numbers of images that simply cannot be adequately viewed in a traditional manner. For example, these techniques have extended into functional imaging, where a section of the body is scanned repeatedly over time, such as to study the flow of fluids or contrast agents and thereby visualize tissue function. Examples of such imaging techniques include CT profusion imaging. Other examples include X-ray angiography and fluoroscopy. Using high-resolution acquisition hardware, studies with image counts in excess of 2,000 images are becoming routine. Given workload and time pressures on radiologists and other viewers of such images, navigation through large image sets is no longer a trivial problem. Even when such images are presented in low resolution, substantial time can be required for paging or viewing large sets of 2-5,000 images in a cine mode. Similar problems exist in other imaging modalities and contexts, such as images produced over a long period of time in PET diagnostic imaging of radionucleotide uptake.
The problem of viewing or navigating through large series of images may be thought of as either a time or space problem. That is, a large group of images may represent a progression through a spatial, as in status, non-functional imaging techniques. Similarly, progression through a large number of images in a series may be posed for images acquired over a period of time, and generally of the same spatial region. The latter series are particularly problematic in that very large number of images may be present that require very substantial times for viewing in advanced cine modes.
There is a need, therefore, for an improved technique for navigating through and viewing images in a series or sequence. There is a particular need for a technique which allows for rapidly locating images of interest, permitting a viewer to rapidly access such images for viewing and analysis.